1. Field of the Invention
This invention relates to measuring devices utilizing a variable color digital display.
2. Description of the Prior Art
A display device that can change color and selectively display digits and characters is described in my U.S. Pat. No. 4,086,514, entitled Variable Color Display Device and issued on Apr. 25, 1978. This display device includes display areas arranged in a suitable display font, such as well known 7-segment display font, which may be selectively energized in groups to display all known characters. Each display segment includes three light emitting diodes for emitting light signals of respectively different primary colors, which are blended within the display segment to form a composite light signal. The color of the composite light signal can be controlled by selectively varying the portions of the primary light signals.
Multimeters with monochromatic digital display are well known and extensively used. Such multimeters, however, have a defect in that they are capable of indicating value of only one measured quantity at a time. They are not capable of simultaneously indicating values of two different quantities, nor are they capable of indicating the relationship of instantly displayed measured value to values measured at other times, nor are they capable of indicating the relationship of instantly displayed measured value to measurement limits.
Although the possibility of a variable color digital display has been previously considered, no practical system utilizing such a display has been made available to public use.